PROJECT SUMMARY/ABSTRACT Refractive error is the most common type of visual impairment in humans and is associated with an increased risk of developing other vision disorders, including primary open angle glaucoma. While an epidemiological association between these two traits is well established, the link is not well understood at a clinical, pathological, and mechanistic level. For this reason, investigating the role of refractive error in the etiology of primary open angle glaucoma can illuminate an important feature in the development of this common and complex vision disorder. This study will address the question of whether the mechanisms that underlie the link between refractive error and primary open-angle glaucoma operate directly through refractive error, or indirectly through shared effects, or both. For this purpose, we will conduct detailed genetic analyses that utilize a unique and powerful resource: the Kaiser Permanente Northern California (KPNC) Genetic Epidemiology Research on Adult Heath and Aging (GERA) cohort on 110,266 subjects. This sample is ideal because it is a single, large, multi-ethnic cohort with existing genome-wide genotype data linked to detailed electronic health records on individuals' refractive error and glaucoma diagnoses. The findings from this study will lay the foundation for mechanistic studies in animal models that recapitulate the features of myopia- induced glaucoma in humans.